This paper presents a proposed rating model that incorporates the fatigue damaging effects of overloads achieved by introducing a "fatigue index" in the rating equation. The aim is to reduce the rating value computed for a bridge in cases where the damage from overloads is expected to be significant. The use of this index does not impose any upper limit on the total number of overloads that may annually be permitted on a bridge. However, because the use of this index will result in a lower rating than those from current equations, it is expected that a certain number of overloads will ultimately be disallowed. This should lead to lower fatigue damage to highway bridges from overloads. To develop the model, overload records were acquired and used in bridge structural analyses to determine the damaging effect of overloads. The study on 5 bridges shows that fatigue damage from overloads can use up 3.5% of fatigue life over a 25-year period if the overload occurrences remain at the current level. The implications of these results are discussed.


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  • Accession Number: 00797587
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 3 2000 12:00AM